1. Field of the Invention
The present invention relates to underground stations and more particularly to access covers for said stations that may be connected to accommodate various size and shaped stations.
2. Description of the Prior Art
Underground stations such as sewage pumping stations are usually custom designed to meet the particular needs of an installation as they pertain to size and configuration. Access covers for such stations must also vary as to size and configuration. Thus, the access covers for large multi-pump stations were either custom designed or formed of several smaller standard size access covers each separately cast into the concrete top of the pumping station. Custom designed covers were expensive to manufacture while the individually cast standard covers were expensive to install because reinforced concrete was required between adjacent covers.
In order to provide standard access covers for the most commonly used installations, at least 8 different size covers were required. The need for such a large number of sizes substantially increased the inventory cost for the cover manufacturers and suppliers.
The installation of multiple access covers significantly increased the cost of the pumping station since the covers had to be either welded or bolted together or separately cast into the concrete top of the station.